Investigation of transcription factor–DNA binding with electrolyte-gated organic transistors

Abstract

Nuclear transcription factor Y (NF-Y) is a CCAAT-binding trimeric protein. The overexpression of the DNA-binding subunit A (NF-YA) results in deregulation of many CCAAT-dependent pro-growth genes in multiple tumor types. Exon 3 alternative splicing of NF-YA results in two different isoforms, NF-YAs (short) and NF-YAl (long), which can promote tumor proliferation or metastasis, respectively. In this work, we developed an electrolyte-gated organic transistor (EGOT) biosensor to study the binding of a NF-YAl-composed NF-Y complex to its consensus sequence. We show that by using the target DNA sequence as a probe, the device detects NF-Y in the range of 1 pM to 10 nM. Control experiments performed with oligonucleotide probes mutated in the consensus sequence exhibit weaker, though not fully hindered, binding to NF-Y compared to the response to unmutated DNA. This behavior confirms that the base pairs near the CCAAT-box also have a role in the transcription factor recognition. Furthermore, we contributed to the advancement of the present state of the art by demonstrating the ability of the EGOT biosensor to detect NF-Y in cell lysate, a fundamental step towards the development of point-of-care (POC) devices for the analysis of biopsies.